The overall objective of the proposed research is to perform a symphonic work providing physiological assessment and validation for hypophysiotropic hormone substances with corticotropin releasing activity, growth hormone releasing or release inhibiting activity, and prolactin releasing or release inhibiting activity, that have been and will be purified and isolated from pig hypothalamic tissue. Synthetic materials and their analogs that have been and will be prepared according to the structure of the natural hypothalamic substances will be evaluated for physiological significance. Various in vivo and in vitro methods for hypothalamic hormones, including radioimmunoassay, active and passive immunization by these hormones, and affinity chromatography using antibodies to the hypothalamic hormones will be used for this purpose.